Some Remarks on the Discovery of ^{244}Md.

Abstract

In two recent papers by Pore etal. and Khuyagbaatar etal., discovery of the new isotope ^{244}Md was reported. The decay data, however, are conflicting. While Pore etal. report two isomeric states decaying by α emission with E_{α}(1)=8.66(2) MeV, T_{1/2}(1)=0.4_{-0.1}^{+0.4} s and E_{α}(2)=8.31(2) MeV, T_{1/2}(2)≈6 s, Khuyagbaatar etal. [Phys. Rev. Lett. 125, 142504 (2020).PRLTAO0031-900710.1103/PhysRevLett.125.142504] report only a single transition with a broad energy distribution of E_{α}=(8.73-8.86) MeV and T_{1/2}=0.30_{-0.09}^{+0.19} s. The data published in Pore etal. are very similar to those published for ^{245m}Md [E_{α}=8.64(2), 8.68(2)MeV, T_{1/2}=0.35_{-0.16}^{+0.23} s [V. Ninov, F. P. Heßberger, S. Hofmann, H. Folger, G. Münzenberg, P. Armbruster, A. V. Yeremin, A. G. Popeko, M. Leino, and S. Saro, Z. Phys. A 356, 11 (1996).ZPAHEX0939-792210.1007/s002180050141] ]. Therefore, we compare the data presented for ^{244}Md in Pore etal. with those reported for ^{245}Md in Ninov etal. and also in Khuyagbaatar etal. We conclude that the data presented in Pore etal. shall be attributed to ^{245}Md with small contributions (one event each) from ^{245}Fm and probably ^{246}Md.